1. Bibliography:

• Azar, B. S., & Hagen, S. A. (2009). Understanding and using English grammar (4th ed.). Pearson Education.

• Eastwood, J. (1994). Oxford guide to English grammar. Oxford University Press.

• Murphy, R. (2019). English grammar in use (5th ed.). Cambridge University Press.

• Celce-Murcia, M., & Larsen-Freeman, D. (1999). The grammar book: An ESL/EFL teacher’s course (2nd ed.). Heinle & Heinle.

• Leech, G., & Svartvik, J. (2002). A communicative grammar of English (3rd ed.). Pearson Education.

• Hewings, M. (2013). Advanced grammar in use (3rd ed.). Cambridge University Press.

• Swan, M. (2005). Practical English usage (3rd ed.). Oxford University Press.

• Yule, G. (2016). Oxford practice grammar: Advanced (2nd ed.). Oxford University Press.

2. Webliography:

• British Council. (n.d.). English grammar: Verbs and tenses. British Council. https://learnenglish.britishcouncil.org/grammar/english-grammar-reference/verbs

• Cambridge University Press. (n.d.). English grammar today: Present simple and continuous. Cambridge Dictionary. https://dictionary.cambridge.org/grammar/british-grammar/

• Grammarly. (n.d.). Verb tenses: The present simple and present continuous. Grammarly. https://www.grammarly.com/blog/verb-tenses/

• Purdue Online Writing Lab. (n.d.). Verb tense consistency. Purdue OWL. https://owl.purdue.edu/owl/general_writing/grammar/verb_tenses.html

• BBC Learning English. (n.d.). Grammar: Present simple and present continuous. BBC. https://www.bbc.co.uk/learningenglish

• EnglishPage.com. (n.d.). Verb tenses. English Page. https://www.englishpage.com/verbpage/verbtenseintro.html

• Perfect English Grammar. (n.d.). All English tenses. Perfect English Grammar. https://www.perfect-english-grammar.com/english-tenses.html

• EnglishClub. (n.d.). Present simple vs. present continuous. EnglishClub. https://www.englishclub.com/grammar/verb-tenses.htm